Fitness and Intelligence

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A variety of research demonstrates increased physical activity and fitness improves learning ability and increases cognitive performance over time.

A young boy is afraid of the dark. How will he find the courage to face his blackened room when the lights go out at bedtime? He must either realize he has nothing to fear in the dark, or he must have confidence in his own strength to contest the things he fears. In time, he will learn the absence of light does not change the basic circumstances of his surroundings. If he is safe in his bedroom with his lights on, he remains safe when the lights go out. He will learn to recognize the shadows of his room and noises of his house as bookcases and creaky floorboards and know they can do him no harm. Or perhaps he scored the winning goal in a soccer game at school that day. Perhaps he defended himself against a bully. Undoubtedly, he will feel more self-confident in light of these physical accomplishments, maybe confident enough to face whatever comes in the dark. So greater intelligence and/or greater physical prowess will contribute to his discovery of courage. And once he finds this courage, he will have a greater urge to further satisfy his curiosity about the darkness, and to find more opportunities for physical achievement.

The previous example illustrates a complementary relationship of virtues, where courage, intelligence and physical fitness combine to support and strengthen one another. In this essay, I examine further data for the connection between fitness and intelligence. A variety of research demonstrates increased physical activity and fitness improves learning ability and increases cognitive performance over time. While some evidence exists in support of the converse relation (that increased mental activity and intelligence is correlated with improved physical fitness), further study is required to substantiate that claim.

The Research: Connecting Fitness & Intelligence

A 2013 study by researchers at the University of Illinois tested 48 nine and ten year old children on their ability to learn new information. The researchers selected 24 students in the top 30% and 24 students in the bottom 30% of aerobic fitness for their age and gender as measured by a treadmill test. Each group contained an approximately equal number of boys and girls with no significant differences in socioeconomic status, ADHD symptoms or scores on an intelligence test. The scientists asked the students to use an iPad to learn the made-up names of ten fictional regions on a map and tested their memories the following day. Within each group of 24, some students only studied on the first day while others received mock tests during their study sessions. On the test day, students in each group were tested either by free recall or cued recall.

Though the researchers observed no differences in initial learning ability, the children in the high-fitness group outperformed those in the low-fitness group during testing, with the former averaging 54.2% correct responses to the latter’s 44.2% correct. The disparity was further exaggerated with the less successful, study-only strategy; high-fitness students outscored low-fitness students 43.0% to 25.8% when both were subject to this condition. Based on these results, the researchers concluded that improved fitness can boost learning and memory in children, and that the fitness-associated performance benefits are greatest in more challenging initial learning conditions.1,2

Furthermore, as demonstrated by a 2013 study by United Kingdom researchers, increased physical activity is correlated with long-term improvements in academic performance. The study measured the amount of time 5,000 eleven year olds born between 1991 and 1992 participated in daily physical activity over three to seven days, as well as how intensely they exercised using an accelerometer. The researchers then compared the children’s activity levels with their academic performance in English, math and science, and found the more moderate to vigorous physical activity a child had, the higher they scored on their tests. The activity-associated performance increase was especially true for girls and their science scores, and this relationship persisted as the girls aged. In general, physical activity at age 11 was linked to academic performance at age 13 for both boys and girls. For boys ages 15 and 16, each 17 minute exercise period produced an increase in the students’ academic scores, while 11 year old girls saw a similar jump in their scores for every 12 minutes a day they exercised.3
This complementary relationship between physical activity and cognitive performance holds for a range of ages. A 2001 study published in the Annals of Behavior Medicine demonstrated that senior citizens who walk regularly showed significant improvement in memory skills compared to their more sedentary counterparts. Walking also improved the subjects’ learning ability, concentration and abstract reasoning, and researchers observed that 57% of people who walked as little as 20 minutes a day reduced their risk of stroke.4 A University of California study observed a positive correlation between brain function and physical activity level (including routine walking and stair-climbing) in a sample of 6,000 women over an eight year period. 24% of the women who walked the least (one half-mile per week) showed significant declines in their cognitive test scores, versus only 17% of the most active women, who averaged 17 miles per week. For every extra mile the subjects walked per week, researchers observed an average of 13% lower chance of cognitive decline.5